Rear Excursion Backrest for Wheelchair Accessible Vehicles

ABSTRACT

A backrest device that normally supports the occupant and moves forward with said occupant during a forward impact/crash event. The device is equipped with a spring activated biased ratcheting mechanism that provides only forward movement, thus reducing the amount of dangerous rear excursion during the rebound phase, as measured by the occupant&#39;s head and torso.

CROSS-REFERENCE TO OTHER APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.16/600,071, filed on Oct. 11, 2019, which claims priority to U.S.Provisional Patent Application No. 62/744,379, filed on Oct. 11, 2018,both of which are incorporated herein by reference.

BACKGROUND Technical Field

The embodiments described and claimed herein relate generally to a headand/or back rest for use in a wheelchair accessible vehicle incombination with conventional tie downs, such as restraint retractors(usually a pair in the front and a pair in the rear) that are secured tothe front and rear of a wheeled mobility device (e.g., a wheelchair).

Background Art

There are 2.2 million wheeled mobility device users in America today.Many users remain in their conventional wheeled mobility device whileboarding and riding private or mass transportation vehicles. Systemshave been developed to secure wheelchair-bound occupants during impacts,including frontal impacts. These systems are typically comprised ofoccupant restraints that include at least one shoulder belt along with alap belt. They also include some form of wheeled mobility devicesecurement that could comprise multiple belts, bumpers, barriers,latches and/or automated grippers. In the most common and simple system,two restraint retractors will be provided to secure the rear of thewheeled mobility device, and two restraint retractors will be providedto secure the front of the wheeled mobility device. Though these deviceshave proven successful in meeting forward excursions during crash tests,many results have indicated that rebound excursions are another serioushazard for the occupant. During the forward impact, the occupant isrestrained by lap and shoulder belts typically constructed from polymersthat exhibit a high degree of elasticity. The wheeled mobility devicetie downs exhibit similar elastic characteristics. This elasticity isbeneficial during the forward excursion because it reduces decelerationof the occupant, and thus reduces the chance and severity of injury tothe occupant. At the same time, the wheeled mobility device is movingforward and its movement limited by the use of tiedowns or similarsystem. The problem occurs during the rebound phase of the event becausethe energy stored in the occupant restraints and wheeled mobility devicetie downs during the forward excursion is returned to the system. As thewheelchair is moving away from the occupant, in this rebound phase, bythe time the wheelchair stops, there is a large gap between the occupantand wheelchair backrest, thus by the time the occupant hits thewheelchair backrest, it has stored a lot of energy and its impact isoften severe and violent.

Head and back rests are currently known in the prior art. However, thoseprior art head and back rests are fixed. In that respect, during aforward crash event the occupant and wheeled mobility device will oftenshift a distance away from the fixed head and back rest while theforward movement loads energy into the restraint devices (i.e., the rearrestraints will stretch and load energy, as will the occupantrestraints). The occupant will then typically see a violent forcereversal as the rear restraints release their stretch and energy on thewheeled mobility device, causing the wheeled mobility device (and itspassenger) to be slammed rearward into the head and backrest. As aresult, occupants are at risk of striking vehicle structures duringrebound which often results in injury and fatality. No known head andback rests on the market today utilize rear excursion and energymanagement during the rebound phase of forward impact or during a rearimpact event.

SUMMARY OF THE PRESENT EMBODIMENTS

Clearly, the prior art devices have limitations which the presentembodiments overcome and make for more effective installation and use.The embodiments described in this document is a novel and innovativedevice that solves excessive rearward excursion of the wheelchair andthus occupant while riding in a vehicle involved in a crash thatproduces severe forward impact. As the occupant moves forward during thecrash event, a robust head and/or back support structure transitionsforward simultaneously at or near the same rate, thus the gap betweenthe wheelchair and backrest remains linear and does not significantlyincrease, unlike traditional systems on the market. The robust headand/or back support structure are equipped with a pivot and biasedratcheting lock mechanism that allows forward movement but preventsrearward movement. The system may contain a friction disc, dampener ordeformable member that will resist minor forward impact events withoutallowing any head and backrest movement. During a significant forwardimpact event the friction device, dampener or deformable member willallow progressive forward movement dependent of severity. The amount offorward displacement will be mapped to closely match typical forwardexcursions experienced in tests. Once the occupant begins the reboundtrajectory, they make contact with the wheelchair backrest and this thenmakes contact with the back support at the same time as the occupantshead contact the back support, resulting in very little relativevelocity and very low resulting impact. The ratcheting lock mechanismrapidly engages and prevents rearward pivoting, thus arresting theoccupant's rearward excursion. The ratcheting lock mechanism can bemanually released when required for stowage or occupant movement.

In some embodiments, the head and/or back support, once positionedadjacent to the head and/or seatback, may be secured to the wheelchairitself (e.g., the wheelchair frame, and not the wheelchair seat back)using some form of tie-down, which may comprise a retractor, belt andhook, or any other manual or automatic belt, strap, cable, chain, or thelike). Tying the head and/or back support to the wheelchair will enhancethe ability of the support to follow the wheelchair during a forwardexcursion and/or will transfer the loads seen by the head and/or backsupport during the occupant's rear excursion to the front wheelchairtie-downs (whereby the loads pass through the wheelchair frame). Thestrength of the head and/or back support can also be enhanced byadditionally or alternatively tying the head and/or back support to someother structure in the vehicle, such as a connection point on the floor,wall, or ceiling of the vehicle, including but not limited to the frontwheelchair tie-downs.

The present embodiments also provide benefits during a rear impact.During the rear impact, the backrest will stop the excursion in the reardirection, and during the rebound (when the passenger and wheeledmobility device will lunge forward), the backrest will follow thewheeled mobility device, minimizing again the re-rebound movement. Inthat respect, even in a rear impact, the backrest will minimize or stoprebound oscillations.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

These and other features, aspects, objects, and advantages of theembodiments described and claimed herein will become better understoodupon consideration of the following detailed description, appendedclaims, and accompanying drawings.

FIG. 1 is a perspective view of a first embodiment of a head and backrest for a wheelchair accessible vehicle;

FIG. 2 is a top view of the head and back rest of the first embodimentin a first position, prior to a frontal accident;

FIG. 3 is a top view of the head and back rest of the first embodimentin a second position, after a frontal accident and just prior to arebound;

FIG. 4 is a perspective view of a partially transparent base of the headand back rest of the first embodiment, showing the ratcheting andrelease mechanisms;

FIG. 5 is a perspective view of a second embodiment of a head and beckrest for a wheelchair accessible vehicle;

FIG. 6 is a side view of the second embodiment.

It should be understood that the drawings are not necessarily to scaleand that the embodiments are sometimes illustrated by graphic symbols,phantom lines, diagrammatic representations and fragmentary views. Incertain instances, details which are not necessary for an understandingof the embodiments described and claimed herein or which render otherdetails difficult to perceive may have been omitted. It should beunderstood, of course, that the inventions described herein are notnecessarily limited to the particular embodiments illustrated. Indeed,it is expected that persons of ordinary skill in the art may devise anumber of alternative configurations that are similar and equivalent tothe embodiments shown and described herein without departing from thespirit and scope of the claims.

Like reference numerals will be used to refer to like or similar partsfrom Figure to Figure in the following detailed description of thedrawings.

DETAILED DESCRIPTION OF THE PRESENT EMBODIMENTS

With reference to FIGS. 1-4, a first embodiment of a backrest 100 isshown for use in combination with a wheeled mobility device securementsystem in a wheelchair accessible vehicle. The backrest includes afloor-mounted base 110 that is attached to the vehicle floor at or nearthe rear of a wheelchair securement area using, for example,conventional fasteners. The base 110, or other structure of the backrest100, may include a bracket 112 to hold a shoulder belt retractor 114.The floor-mounted base 110 supports and provides a pivot point for avertical stanchion or pivot member 130. Although the pivot is shownaligned with a vertical axis, it is contemplated that the pivot may bealigned with either a vertical, horizontal, or other axis. Moreover,while the base 110 is shown to be floor-mounted, it is contemplated thatthe base may be a wall- or ceiling mounted structure.

As mentioned, the pivot member 130, as shown, is configured to pivotabout a vertical axis. It includes a shoulder belt guide 132 with atrack structure 134 that allows the shoulder belt to be verticallyadjustable to multiple fixed positions at different heights. Althoughnot shown, a shoulder belt would extend from the retractor 114 andthrough the guide 132, and may be pulled around the shoulder of anoccupant to secure the passenger. The pivot member 130 also supports atelescoping arm 150 comprising a first member 152 and a second member154. The length of the telescoping arm can be adjusted by sliding thesecond member 154 relative to the first member 152, and the relativepositions of the first and second members 152, 154 can be fixed usinglock member 156. The telescoping arm 150 is fixed at its base to thepivot member 130, whereby the arm 150 will rotate with the pivot member,about a vertical axis. At its free end, the telescoping arm 150 includesa bracket 158 for attachment to a contact member 170 that may comprise apadded or compressible material. The bracket 158 may include multipleapertures or other structures that allow the contact member to bevertically adjustable to multiple fixed positions at different heights.

The contact member 170 may be short and configured to support solely aback of the occupant, or may be long (as shown) and configured tosupport both a back and head of the occupant. For the avoidance ofdoubt, and for purposes of simplicity, the term “backrest” is usedherein to refer to any support provided for a back and/or head of anoccupant. As best shown in FIGS. 2-3, the contact member 170 includes acurved front surface 172, whereby the contact member 170 will alwaysmake “normal” (i.e., perpendicular) contact with the wheeled mobilitydevice and/or occupant.

By virtue of the pivotable connection between the pivot member 130 andthe base 110, the contact member 170 will be able to follow the wheeledmobility device (and occupant) during a forward crash event, as is bestshown in FIGS. 2-3. More particularly, in one embodiment, the forwardmomentum of the arm 150 and contact member 170 will cause the pivotmember to rotate from the first position shown in FIG. 2 to the secondposition shown in FIG. 3, in a forward impact event. Note that otherembodiments are contemplated that do not use a pivoting contact member170, but rather rely upon, for example, linear movement of the contactmember. For example, the backrest could by constructed with a scissorsmechanism, linear slides, and/or struts whereby the contact member 170will follow the back of the wheeled mobility device in a lineardirection.

Moreover, while the preferred embodiment uses the momentum of thebackrest 100 as the motive force for moving the contact member 170 inclose proximity to the back of the wheeled mobility device, othersources of motive force are contemplated. For example, in otherembodiments, springs or other similar devices may be used to bias thecontact member 170 against the back of the wheeled mobility device,whereby the contact member 170 will follow the back of the wheeledmobility device during a forward impact. In yet other embodiments,pyrotechnic devices could be used to cause the contact member 170 tofollow the back of the wheeled mobility device in the event of anaccident, whereby the pyrotechnic device is activated in response tosensors that detect a forward impact. The pyrotechnic device could movethe entire contact member 170 forward, or could simply expand thecontact member 170, using an internal bladder or the like, whereby thefront surface of the contact member 170 would follow the wheeledmobility device forward. A similar bladder type expansion device couldbe also be used in the absence of pyrotechnics. For example, theexpansion device could expand upon the release of gas or other fluidsstored in a canister. Alternatively, depending upon the necessaryresponse time, compressors or other similar compression devices could beused to expand the bladder during an accident. In yet other embodiments,the backrest 100 could employ gas, pneumatic, or electric struts thateither bias the contact member 170 against the back of the wheeledmobility device, or respond quickly to push the contact member 170forward in the event that a sensor detects a forward impact, whereby thebackrest. In yet other embodiments, the contact member 170 could bedirectly connected to the wheeled mobility device using belts, buckles,or straps, whereby the wheeled mobility device will pull the contactmember 170 when it moves forward during a forward impact. A similarresult could be achieved by attaching the contact member 170 to thehooks of the rear wheeled mobility device tie-downs (in which case thecontact member 170 could be said to be indirectly attached to thewheeled mobility device).

The base 110 contains a spring-loaded ratchet 116 and pawl 118, 120assembly that allows the pivot member 130 to rotate, in this case in acounterclockwise direction, to automatically positive-lock to preventclockwise rotation. In this case, the ratchet 116 is fixed to the bottomend of the pivot member 130, and the pawls 118, 120 are pivotallyattached to the base 110. The springs (not shown) urge the pawls 118,120 into contact with the ratchet 116. The base 110 includes a releasemember 122, in this case a plate, that include slots 124, 126 thatengage with pins 125, 127 to pull the pawls 118, 120 out of contact withthe ratchet 116, whereby the vehicle operator can pivot the arm 150 andcontact member 170 in a clockwise direction, away from the wheeledmobility device, so that the occupant can exit the vehicle through therear doors.

In alternative embodiments, the stanchion 130 may be fixed to the floorof the vehicle, and the ratchet and pawl mechanism may be located at theconnection point between the stanchion 130 and the arm 150, whereby thearm 150 is not fixed to but rather rotates relative to and about thestanchion 130. In yet other embodiments, the stanchion can be omittedentirely, and the arm 150 can be fixed directly to the base 110, whichin turn could be mounted to any structure in the vehicle—e.g., floor,wall, or ceiling.

Although the invention has been described in terms of a wheeled mobilitydevice that is forward facing with respect to the vehicle direction oftravel, it is contemplated that the backrest could be useful in side-and rear-facing systems. In that respect, the term “forward impact”should be taken to mean any impact in a forward direction with respectto the direction the wheeled mobility device occupant is facing (withoutrespect to the direction the vehicle is facing). Similarly, the term“rear impact” should be taken to mean any impact in a rearward directionwith respect to the direction the wheeled mobility device occupant isfacing.

As designed, the head and back rest 100 is easily adjustable andfacilitates simplified loading and unloading of wheelchair-boundoccupants with less time, effort and skill. The probability of errorduring positioning becomes greatly reduced as the device is allowed tomove freely against the occupant and/or wheelchair. The simplifieddesign and reduced part-count also produce cost and weight reductions.Minimized rear excursion provides an added layer of safety for theoccupant by preventing impact with the vehicle interior whereinstallations don't allow for typical displacements found in crashevents.

Turning now to FIGS. 5-6, a second embodiment of a backrest 200 is shownin combination with a wheeled mobility device securement system 300 in awheelchair accessible vehicle. The backrest 200 of the second embodimentis largely the same as the backrest 100 of the first embodiment, in thatit may also include a floor-mounted base 210, a vertical stanchion orpivot member 230, a bracket 212 that holds a shoulder belt retractor214, a shoulder belt guide 232 that receives the shoulder belt 215 fromthe shoulder belt retractor 214 and is height adjustable via track 234,a telescoping (or fixed length) arm 250, and a bracket 258 forattachment to a contact member 270. Notably, the internals of thefloor-mounted base 210 may be configured the same as the floor-mountedbase 110 of the first embodiment. Notably, in the second embodiment, thepivot member 230 telescopes to make the contact memberheight-adjustable. In addition, the backrest 200 includes a tie-down 280that may be used to secure the contact member 270 to the wheelchair, thewheeled mobility device securement system 300, or the vehicle itself. Inthis case, the tie-down 280 is an automatic locking retractor with abelt 282 and hook 284. While the tie-down 280 is shown secured to therear-side and bottom right corner of the contact member, it could besecured to any other portion of the backrest 200, such as the arm 250and/or bracket 258. It is contemplated that the vehicle operator, afterpositioning the contact member 270 adjacent to the seatback, will securethe hook 284 to a structure forward of or on plane 290 with theconnection point between the tie-down and the contact member 270 (i.e.,a plane have dimensions in the vertical and lateral directions). Asshown, the hook 284 is secured to the frame of the wheelchair, althoughit could be secured to the hook eyes of the rear retractors, any portionof the front retractors, or any portion of the vehicle. As discussedabove, tying the contact member 270 to the wheelchair or other structureof the securement system 300 or vehicle will enhance the ability of thecontact member 270 to follow the wheelchair seatback and/or willstrengthen the backrest 200 by splitting the load of a rear excursionbetween the pivot member 230 and the tie-down 280.

Although the inventions described and claimed herein have been describedin considerable detail with reference to certain embodiments, oneskilled in the art will appreciate that the inventions described andclaimed herein can be practiced by other than those embodiments, whichhave been presented for purposes of illustration and not of limitation.Therefore, the spirit and scope of the appended claims should not belimited to the description of the embodiments contained herein.

We claim:
 1. A moveable backrest intended for a use in combination witha wheeled mobility device securement system in a wheelchair accessiblevehicle, the moveable backrest comprising: an arm having a pivot axis ata first end and a contact member at a second end; a ratchet and pawlmechanism that permits the arm to rotate about its axis in a firstdirection, and precludes the arm from being rotated about its pivot axisin an opposite direction.
 2. The moveable backrest of claim 1 installedin the wheelchair accessible vehicle and being disposed at the rear of awheeled mobility device securement area, whereby the ratchet and pawlmechanism permits the arm to rotate in the first direction toward afront of the wheeled mobility device securement area.
 3. The moveablebackrest of claim 2, wherein the pivot axis is aligned with an axisselected from the group including a vertical axis and a horizontal axis.4. The moveable backrest of claim 2, wherein the ratchet and pawlmechanism is disposed in a base that is fixed to a structure selectedfrom the group including the wheelchair accessible vehicle, a floor ofthe wheelchair accessible vehicle, a wall of the wheelchair accessiblevehicle, and a ceiling of the wheelchair accessible vehicle.
 5. Themoveable backrest of claim 4, wherein the base include a release memberfor disengaging the pawl from the ratchet to allow for free rotation ofthe arm.
 6. The moveable backrest of claim 2, further comprising astanchion pivotally fixed at a base to the wheelchair accessiblevehicle, wherein the arm is rigidly fixed to and pivots with thestanchion.
 7. The moveable backrest of claim 2, further comprising astanchion rigidly fixed at a base to the wheelchair accessible vehicle,wherein the arm is pivotally attached to the stanchion.
 8. The moveablebackrest of claim 7, wherein the ratchet is fixed to a bottom end of thestanchion and the pawl is fixed to the base.
 9. The moveable backrest ofclaim 7, wherein the pawl is fixed to a bottom end of the stanchion andthe ratchet is fixed to the base.
 10. The moveable backrest of claim 2,wherein the arm includes a first member and second member, wherein thefirst member telescopes relative to second the second member to change alength of the arm.
 11. The moveable backrest of claim 10, furtherincluding a locking member for locking the position of the second memberrelative to the first member.
 12. The moveable backrest of claim 2,wherein the contact member includes a curved front surface.
 13. Themoveable backrest of claim 1, wherein the contact member includes acurved front surface.